Air supply system and method

ABSTRACT

An air supply system of an atmosphere control system is provided. The air supply system may incorporate features to condition an air stream before the air stream is directed toward an air separation device. A temperature of the air stream to the air separation device may be reduced to help condense moisture in the air stream. The air stream with the lowered temperature may be directed through a moisture removal device to help remove moisture in the air stream. The air stream may also be directed through a particle removal device to help remove particles in the air stream. The air stream may be directed through a heat recovery device to regulate the temperature of the air stream before being directed to the air separation device.

FIELD

The disclosure herein relates to an air supply system of an atmosphere control system such as, for example, in a storage unit. More specifically, the disclosure is directed to an air supply system that may include features to help condition an air stream before the air stream is directed through an air separation device (e.g. a nitrogen separation system), and a method thereof.

BACKGROUND

In a storage unit (e.g. a transport unit), atmosphere in a storage space of the storage unit may be controlled to help prolong the shelf life of perishable goods such as, for example, fruits and vegetables. In some cases, for example, an atmosphere control system may be configured to separate nitrogen from the air and supply the nitrogen to the storage space, so that an oxygen level and/or carbon dioxide level in the storage space may be controlled. A nitrogen and/or CO2 and/or O2 separation device, such as a nitrogen separation membrane, may be included in the atmosphere control system to help separate the nitrogen from the air.

SUMMARY

Embodiments as disclosed herein provide systems, apparatuses and methods to condition an air stream before the air stream is directed through an air separation device to help increase or maintain an efficiency of the air separation device.

In some embodiments, an atmosphere control system, for example, in a storage unit (e.g. a transport unit) may generally include an air supply system and an air separation device. The air supply system may incorporate features to condition an air stream before the air stream is directed toward the air separation device. The air supply system may be configured, for example, to help regulate a temperature of the air stream, and/or remove moisture and/or particles from the air stream. By regulating a temperature of the air stream, a separation efficiency of the air separation device can be increased and an overall performance of the atmosphere control system can be increased. The air supply system may help increase the efficiency and/or lifespan of the air separation system. The air supply system may also form a heat exchange relationship with a refrigeration unit (e.g. a transport refrigeration unit (TRU)) so that a cooling or hot part of the refrigeration system may be used to condition the air stream in the air supply system.

In some embodiments, the air supply system may include a first heat exchanger, a second heat exchanger, and a moisture reduction device. In some embodiments, the first heat exchanger may be configured to lower a temperature of an air stream supplied to the air supply system. Lowering the temperature of the air stream may help saturate the moisture in the air stream to form droplets, which can help remove the moisture from the air stream.

In some embodiments, the moisture reduction device may be configured to remove moisture (e.g. droplets) in the air stream after the temperature of the air stream is reduced in the first heat exchanger. In some embodiments, the second heat exchanger may be configured to raise the temperature of the air stream after the air stream is directed out of the moisture reduction device.

In some embodiments, the air supply system may include a particle reduction device, which may be configured to remove particles in the air stream. In some embodiments, the particle reduction device may be positioned downstream of the moisture reduction device to receive the air stream. In some embodiments, the air supply system may also include a chemical pollution reduction device (e.g., an activated carbon filter) for removing chemical pollution (e.g., oil vapors, ozone, hydrocarbons, etc.). In these embodiments, the device can be positioned downstream of the particle reduction device.

In some embodiments, the first heat exchanger may be configured to form a heat exchange relationship with a cold part of the refrigerant system such as, for example, an evaporator of the refrigeration. The cold part of the refrigeration system generally refers to components, devices or refrigerant lines of the refrigeration system that may carry a refrigerant having a temperature that is lower than the ambient temperature. In some embodiments, the first heat exchanger may be configured to be positioned inside a storage space of the temperature controlled storage unit so that the relatively cold air in the storage space of the storage unit may be used to lower the temperature of the air stream.

In some embodiments, the second heat exchanger may be configured to form a heat exchange relationship with a hot part of the refrigeration system such as, for example, a condenser of the refrigeration system.

In some embodiments, an air compressor may be configured to provide an air stream to the air supply system. In some embodiments, the second heat exchanger may be configured to form a heat exchange relationship with the air stream provided by the air compressor.

In some embodiments, the air supply system may include a first temperature sensor configured to measure a first temperature of the air stream directed out of the first heat exchanger and a second temperature sensor configured to measure a second temperature of the air stream directed out of the second heat exchanger.

In some embodiments, a method of conditioning an air stream for an air separation device may include providing an air stream; lowering a temperature of the air stream; removing moisture from the air stream with the lowered temperature; and increasing the temperature of the air stream after removing moisture from the air stream.

In some embodiments, the method of conditioning the air stream may include removing particles from the air stream. In some embodiments, removing particles from the air stream may be conducted after removing moisture from the air stream. Also, in some embodiments, an additional filter can be provided to remove chemical pollution from the air stream.

In some embodiments, lowering the temperature of the air stream may include forming a heat exchange relationship between the air stream with an evaporator of a refrigeration system. In some embodiments, increasing the temperature of the air stream after removing moisture from the air stream may include forming a heat exchange relationship between the air stream with a condenser of a refrigeration system. In some embodiments, increasing the temperature of the air stream after removing moisture from the air stream may include forming a heat exchange relationship between the air stream and the air stream compressed by a compressor.

In some embodiments, the storage unit can be a TRU.

Other features and aspects of the systems, methods, and control concepts will become apparent by consideration of the following detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference is now made to the drawings in which like reference numbers represent corresponding parts throughout.

FIG. 1 illustrates one embodiment of an atmosphere control system, which includes an air supply system configured to condition an air stream supplied to an air separation system of the atmosphere control system.

FIG. 2 illustrates an atmosphere control system, according to another embodiment.

FIG. 3 illustrates an atmosphere control system, according to yet another embodiment.

FIG. 4 illustrates an atmosphere control system, according to another embodiment.

FIG. 5 illustrates a truck trailer that is equipped with an atmosphere control system.

DETAILED DESCRIPTION

Atmosphere in a storage unit (e.g. a cargo space of a transport unit) may be controlled to help, for example, prolong the shelf life of perishable goods. In some cases, for example, components separated from air (e.g. nitrogen, and/or CO2, and/or O2) may be supplied to the storage space to replace oxygen and/or carbon dioxide in the storage space, which may help reduce a ripening effect of the perishable goods. A nitrogen separation device, such as a nitrogen separation membrane, may be used to help separate nitrogen from the air. A separation efficiency of the nitrogen separation device, such as the nitrogen separation membrane, may be affected, for example, by a temperature, humidity and or a particle content of the air supplied to the nitrogen separation device.

An air supply system that incorporates features to condition an air stream before the air stream is directed through an air separation device (e.g. a nitrogen separation membrane) and a method of conditioning the air stream supplied to the air separation device are describe herein. In some embodiments, a temperature of the air stream may be reduced to help saturate moisture in the air stream. In some embodiments, the air stream with the lowered temperature may be directed through a moisture removal device to help remove moisture in the air stream. In some embodiments, the air stream may be directed through a particle removal device to help remove particles in the air stream. In some embodiments, the air supply system may also be directed through a chemical pollution reduction device (e.g., an activated carbon filter) for removing chemical pollution (e.g., oil vapors, ozone, hydrocarbons, etc.). In some embodiments, the air stream may be directed through a heat recovery device to regulate the temperature of the air stream before the air stream being directed through an air separation device. In some embodiments, the air stream may be directed through an air separation device such as, for example, a nitrogen separation membrane.

References are made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration of the embodiments in which the embodiments may be practiced. It is to be understood that the term used herein are for the purpose of describing the figures and embodiments and should not be regarded as limiting the scope. The term “air separation” is generally defined as separation of components (e.g. nitrogen, oxygen, carbon dioxide and/or argon) from atmosphere air.

Referring to FIG. 1, an atmosphere control system for a storage unit 120 is described. The atmosphere control system may include an air supply system 100, an air separation device 110 and an air compressor 145. The air supply system 100 is configured to condition an air stream 105 (illustrated in FIG. 1 as arrows) before the air stream 105 is provided to the air separation device 110 (e.g. a nitrogen separation membrane). The air separation device 110 may be configured to, for example, separate nitrogen from the air stream 105 and provide the separated nitrogen to a storage space 122 of a storage unit 120. It is to be appreciated that the air separation device 110 may be configured to separate other type(s) of gas from the air such as, for example, oxygen, argon, carbon dioxide, or other rare inert gases. In some embodiments, the air separation device 110 may be configured to separate water vapor, ethylene, etc. In some embodiments, the air separation device 110 may be configured to separate different components of the air at, for example, different rates.

The term “air separation” refers to a process to separate atmospheric air into different components, typically nitrogen and oxygen, and sometimes also argon, carbon dioxide, or other rare inert gases. Various types of air separation device 110 may be used. For example, the air separation device 110 may be a pressure swing membrane, or a cryogenic distillation device. It is to be appreciated that other methods and systems may also be used to remove components from the air, such as for example, sorption (absorption/desorption or chemisorption) or catalytic conversion. It is to be appreciated that the atmosphere control system as described herein can be configured to be suitable for various methods and systems for air separation or components removal.

The air stream 105 may be provided to the air supply system 100 by, for example, the air compressor 145. The compression of the air stream 105 by the air compressor 145 may increase a temperature of the air stream. In addition, the air stream 105 may include some moisture, and/or solid and liquid particles. When the air compressor 145 compresses the air stream 105, the moisture and particle concentrations in the air stream 105 may be increased. An efficiency of the air separation device 110 may be affected by, for example, the moisture and/or particle content of the air stream 105. To help increase and/or maintain the efficiency of the air separation device 110, the air supply system 100 may be configured to include features to help condition the air stream 105, which may include removing moisture and/or particles from and/or regulating a temperature of the air stream 105, so that the air stream 105 provided to the air separation device 110 may have desired air parameters (e.g. a moisture content, a particle content, a temperature) to for desired performance of the air separation device 110.

Generally, the air supply system 100 may be configured to lower the temperature of the air stream 105 to increase a relative humidity and/or achieve air saturation with the moisture content. The moisture may start to create droplets, which may be removed relatively easily. The same principle may not only apply to a water content, but may also apply to, for example, oil fume or other types of vapor. The droplet formation may also help reduce particle content in the air stream 105. After removing the moisture and/or particle content, the air supply 100 may be configured to condition (e.g. heat up) the air stream 105 so that the temperature of the air stream 105, for example, may be in a desired range for the desired performance of the air separation device 110.

The air supply system 100 illustrated in FIG. 1 includes a first heat exchanger 130, a moisture reduction device 132, a particles reduction device 134, and a second heat exchanger 136. The air supply system 100 also includes a first valve 137 and a second valve 139. The first and second valves 137, 139 may be configured to regulate the air stream 105 (e.g. directions and/or an amount of the air stream 105) in the air supply system 100. The air supply system 100 can also include a first temperature sensor 141 and a second temperature sensor 143.

The air stream 105 may be provided to the air supply system 100 by the air compressor 145. The first heat exchanger 130 may be configured to lower the temperature of the air stream 105 when the air stream 105 flows through the first exchanger 130. The first heat exchanger 130 may be, for example, thermally coupled to a cold part of a refrigeration system 140 so that the first heat exchanger 130 forms a heat exchange relationship with the cold part of the refrigeration system 140. In some embodiments, the first heat exchanger 130 can form a heat exchange relationship with, for example, heat exchanger tubes of an evaporator of the refrigeration system 140, so that cold refrigerant in the evaporator of the refrigeration system 140 may help lower the temperature of the air stream 105 in the first heat exchanger 130. The first heat exchanger 130 may be, for example, a tube-in-shell or tube-by-tube design. The cold part of the TRU generally refers to components, devices or refrigerant lines of the TRU that may carry a refrigerant having a temperature that is lower than the ambient temperature. In some embodiments, the first heat exchanger 130 may not form a direct heat exchange relationship with the refrigeration system 140. The first heat exchanger 130 may be, for example, positioned in the storage space 122, and cold air in the storage space 122 may help lower the temperature of the air stream 105 in the first heat exchanger 130. In some embodiments, the first heat exchanger 130 may be positioned in an airflow directed out of the refrigeration system 140.

The air stream 105 may then be directed through the moisture reduction device 132 to remove, for example, water droplets in the air stream 105. The air stream 105 may be directed through the particle reduction device 134 to remove, for example, particles in the air stream 105. It is to be appreciated that in some embodiments, the particle reduction device 134 may also be positioned upstream of the moisture reduction device 132.

The air stream 105 leaving the particle reduction device 134 may be, for example, directed through the second heat exchanger 136 to help regulate the temperature of the air stream 105 before the air stream 105 is directed through the air separation device 110. Typically, the temperature of the air stream 105 directed out of the particle reduction device 134 may be relatively low, because the temperature of the air stream 105 may be lowered in the first heat exchanger 130. The second heat exchanger 136 may be configured to increase the temperature of the air stream 105 to, for example, the desired temperature for the desired performance of the air separation device 110.

In the illustrated embodiment of FIG. 1, the second heat exchanger 136 may help form a heat exchange relationship between the air stream 105 b directed out of the particle reduction device 134 and the air stream 105 a directed out of the air compressor 145. Because the air stream 105 a directed out of the air compressor 145 typically has a relatively high temperature, the second heat exchanger 136 may help increase the temperature of the air stream 105 b directed out of the particular reduction device 134, which may have the relatively low temperature. It is to be appreciated that the second heat exchanger 136 may also be thermally coupled to other heat source(s) that is suitable for heating the air stream 105 b, such as forming a heat exchange relationship with a hot part (e.g. a condenser) of the refrigeration system 140. The hot part of the refrigeration system generally refers to components, devices or refrigerant lines of the TRU that may carry a refrigerant having a temperature that is higher than the ambient temperature.

In some embodiments, there is no need to regulate an amount and/or direction of air stream 105. In some embodiments, it may be desirable to regulate the amount and/or direction of air stream 105. It is to be appreciated that one or more valves may be used in the air supply system 100 to regulate, for example, an amount and/or a direction of the air stream 105. In the illustrated embodiment of FIG. 1, the first valve 137 and the second valve 139 may be configured so that the air stream 105 may by-pass the first and/or second heat exchangers 130, 136 and be directed through the moisture reduction device 132 directly. The first and second valves 137, 139 may also be configured to regulate the amount of air stream 105 directed to the first and/or second heat exchangers 130, 136. For example, the first and second valve 137, 139 may be three-way valves and the amount of air stream directed through the first heat exchanger 130 and/or the second heat exchanger 136 may be regulated.

In some embodiments, the first valve 137, the second valve 139 and the line connecting the first and second valves 137, 139 may not be necessary. The air stream 105 can be directed into the second heat exchanger 136, the first heat exchanger 130 and the moisture reduction device 132 without going through a valve configured to control an amount or direction of the air stream 105.

It is to be appreciated that the embodiment in FIG. 1 is exemplary. Generally, one or more valves may be included in the air supply system 100 so that the first and/or the second heat exchangers 130, 136 may be by-passed. For example, when the environment is relatively warm, the second heat exchanger 136 may be by-passed. Generally, the factors affecting the decision on whether to by-pass the second heat exchanger 136 may include: an amount of heat transferred in the first and/or second heat exchangers 130, 136, the temperature of the air stream 105 directed through the air compressor 145, an ambient temperature, a cargo temperature, a space temperature of the storage space 122, an operation condition of the air supply system 100 and/or an operation mode (e.g. on or off) of the refrigeration system 140.

In operation, the first and second valves 137, 139 may be modulated to control the air stream 105 enters and/or by-passes the first and/or second heat exchangers 130, 136. By controlling the amount of air stream 105 entering or by-passing the first and/or second heat exchangers 130, 136, the temperature of the air stream 105 may be controlled.

In the illustrated embodiment of FIG. 1, the air supply system 100 includes the first and second temperature sensors 141, 143. The first and second valves 137, 139 may be modulated so that temperatures measured by the first and/or second temperature sensors 141, 143 may be at desired temperatures. The first temperature sensors 141 may be configured to measure a first temperature of the air stream 105 before the air stream 105 is directed through the moisture reduction device 132. The first temperature of the air stream 105 may be, for example, a temperature that is at or lower than a saturation temperature of the moisture in the air stream 105. The valves 137, 139 may be modulated and/or throttled (e.g. on and off) to meet the desired first temperature.

The first temperature sensor 141 can help provide temperature information of the air stream 105 before the air stream 105 is directed into the moisture reduction device 132. It is to be appreciated that the first temperature sensor 141 is optional, and is not necessary in some embodiments.

The second temperature sensor 143 may be configured to measure a second temperature of the air stream 105 before the air stream 105 is directed through the air separation device 110. The second temperature of the air stream 105 may be, for example, a desired temperature for obtaining optimal efficiency of the air separation device 110. The valves 137, 139 may also be modulated and/or throttled (e.g. on and off) to meet the desired second temperature.

It is to be appreciated that the temperature of the air stream 105 may also be regulated by regulating the first and/or second heat exchangers 130, 136. For example, by regulating an amount of heat exchanged in the first and/or second heat exchangers 130, 136.

The air supply system 100 provides a way to regulate the temperatures of the air stream 105. The air supply system 100 may be configured to lower the temperature of the air stream 105 so as to help remove moisture content from the air stream 105, and/or provide the desired temperature of the air stream 105 for the air separation device 110. The air compressor 145 configured to provide the air stream 105 to the air supply system 100 may be a variable speed or a fixed speed compressor. By using the temperature sensors 141, 143 to measure the temperatures of the air stream 105, and regulating the air supply system 100 based on the measured temperatures, the temperatures of the air streams 105 directed toward the moisture reduction device 132 and the air separation device 110 may be controlled to meet the desired temperatures. This may help increase the efficiency and/or the lifespan of the air separation device 110.

In some embodiments, the air compressor 145 may be a variable speed compressor that can regulate a temperature of the air stream 105 by changing the speed of the compressor. Generally, the temperature of the air stream 105 is relatively high when the operation speed of the variable speed air compressor 145 is relatively high. However, using the variable speed compressor 145 to change the temperature of the air stream 105 may affect an amount of the air stream 105 provided to the air separation device 110. The air supply system 100 as disclosed herein may add another way to regulate the temperature of the air stream 105 without affecting the amount of air stream 105 provided to the air separation device 110. In some embodiments, when the air compressor 145 has a fixed operation speed, the temperature of the air stream 105 may not be regulated by changing the speed of the compressor. The air supply system 100 as disclosed herein may regulate the temperature of the air stream 105 without changing the operation speed of the air compressor 145 or affecting the amount of the air stream 105 provided to the air separation device 110.

A method of conditioning an air stream for an air separation device may include: providing an air stream (e.g. the air stream 105 provided by the air compressor 145); lowering a temperature of the air stream (e.g. lowering the temperature of the air stream 105 in the first heat exchanger 130); removing moisture from the air stream with the lowered temperature (e.g. removing the moisture in the air stream 105 in the moisture reduction device 132; and increasing the temperature of the air stream after removing moisture from the air stream (e.g. increasing the temperature of the air stream 105 in the second heat exchanger 136).

In some embodiments, the method of conditioning the air stream may include removing particles from the air stream (e.g. removing the particles from the air stream 105 in the particle reduction device 134). In some embodiments, removing particles from the air stream may be conducted after removing moisture from the air stream.

In some embodiments, lowering the temperature of the air stream may include forming a heat exchange relationship between the air stream and a cold part (e.g. an evaporator) of a refrigeration system. In some embodiments, increasing the temperature of the air stream after removing moisture from the air stream may include forming a heat exchange relationship between the air stream with a hot part (e.g. a condenser) of a refrigeration system. In some embodiments, increasing the temperature of the air stream after removing moisture from the air stream may include forming a heat exchanger relationship between the air stream and the air stream compressed by an air compressor (e.g. the air stream compressed by the air compressor 145).

It is to be appreciated that in some embodiments, an operational condition(s) (e.g. purity and/or concentration of air separated by the air separation device 110 may be measured. The measurement can help protect the air separation device 110 from abnormal operation. The embodiments as disclosed herein can help protect the air separation device 110 from, for example, water damage. The embodiments as disclosed herein can also help the efficiency of the air separation device 110 by regulating the temperature of the air stream 105 directed into the air separation device 110.

FIGS. 2-4 illustrate several additional embodiments of an atmosphere control system. It is appreciated that the embodiments as illustrated in FIGS. 1-4 herein may be combined and/or altered.

FIG. 2 illustrates an air supply system 200 that includes a refrigeration system 240, a three-way valve 235 positioned downstream of a particles reduction device 234, and upstream of a second heat exchanger 236. The three-way valve 235 may direct an air stream 205 into an air separation device 210 without going to a second heat exchanger 236. When, for example, an atmosphere temperature is relatively high, the second heat exchanger 236 may not be necessary to achieve a desired air stream temperature for the air separation device 210. The three-way valve 235 may be used to direct the air stream through the air separation device 210, bypassing the second heat exchanger 236. The air supply system 200 can also include a temperature sensor 243.

FIG. 3 illustrates another air supply system 300 that is configured to direct an air stream 305 through a heat exchanger 338 that is thermally coupled to a condenser 350 of a refrigeration system 340. Refrigerant in the condenser 350 may be directed through the third heat exchanger 338 to exchange heat with an air stream 305 in the third heat exchanger 338. In the illustrated embodiment, an expansion device 355 may be used to expand the refrigerant from the condenser 350 to lower the temperature of the refrigerant flowing into the third heat exchanger 338. By controlling the expansion device 355 to regulate for example a flow rate, direction, and/or temperature of the refrigerant, desired heat exchange in the third heat exchanger 338 may be achieved, which can help the air stream 305 to maintain or reach a desired temperature when entering the air separation device 310. The air supply system 300 can also include other heat exchanger(s), e.g. a second heat exchanger 336, to regulate temperature of the air stream 305.

FIG. 4 illustrates another air supply system 400 where a first heat exchanger 430 may be thermally coupled to a refrigeration system 440 downstream of an expansion device 460 of the refrigeration system 440. Relatively cold refrigerant (e.g. refrigerant expanded by the expansion device 460) can be directed through the first heat exchanger 430 to exchange heat with an air stream 405. In the illustrated embodiment, the first heat exchanger 430 is also in fluid communication with a flow control device 461 configured to control, for example, a flow rate of the refrigerant. By controlling the flow control device 461 and/or the expansion device 460, a flow rate, direction, and/or a flow temperature of the refrigerant entering the first heat exchanger 430 may be controlled to achieve a desired amount of heat exchange in the first heat exchanger 430. This can help control the temperature of the air stream 405 entering a moisture removal device 432.

FIG. 5 illustrates a trailer truck 530 that is equipped with a TRU 532 and an atmosphere control system 560, which may be configured to regulate air parameters inside a cargo space 522 of a trailer 520. In some embodiments, for example, the atmosphere control system 560 may be configured to increase a nitrogen concentration and reduce an oxygen concentration and/or a carbon dioxide concentration in the cargo space 522.

The atmosphere control system 560 includes an air supply system 500 and an air separation device 510. The air supply system 500 may be configured to condition an air stream (such as, for example, the air stream 105 in FIG. 1) being directed toward the air separation device 510, so that the air stream directed to the air separation device 510 may have an optimal parameter(s) for the operation of the air separation device 510. The air supply system 500 may be configured to, for example, remove moisture and/or particles from the air stream, and/or regulate a temperature of the air stream.

The atmosphere control system 560 may be integrated into the TRU 532, with the appreciation that the atmosphere control system 560 may be separate from the TRU 532. In some embodiments, the atmosphere control system 560 may form a heat exchange relationship(s) with the TRU 532, so that a cold part (e.g. an evaporator) and/or a hot part (e.g. a condenser) may be used to condition (cool down and/or heat up) the air stream in the atmosphere control system 560.

It is to be appreciated that the embodiments as described herein work with other types of transport unit such as, for example, a railway car, a shipping container, or an airplane cargo unit. The embodiments as described herein may also be used with a stationary storage unit such as, for example, a refrigerator, or a cold room.

It is to be appreciated that the embodiments as described herein may work with other types of air separation devices. For example, some membranes may be configured to separate other components from the atmosphere air. Generally, the embodiments as disclosed herein provide systems, apparatuses and methods to condition an air stream before the air stream is directed through an air separation device to help increase or maintain an efficiency of the air separation device.

Aspects

Any of aspects 1-12 can be combined with any of aspects 13-20. Any of aspects 13-17 can be combined with any of aspects 18-20.

Aspect 1. An air supply system, comprising:

-   -   a first heat exchanger;     -   a second heat exchanger; and     -   a moisture reduction device;     -   wherein the first heat exchanger is configured to lower a         temperature of an air stream supplied to the air supply system,     -   the moisture reduction device is configured to remove moisture         in the air stream after the air stream is directed out of the         first heat exchanger; and     -   the second heat exchanger is configured to raise the temperature         of the air stream after the air stream is directed out of the         moisture reduction device.         Aspect 2. The air supply system of aspect1, further comprising:     -   a particle reduction device, wherein the particle reduction         device is configured to remove particles in the air stream after         the air stream is directed out of the moisture reduction device.         Aspect 3. The air supply system of any of aspects 1-2, wherein         an air stream to the air supply system is provided by an air         compressor.         Aspect 4. The air supply system of any of aspects 1-3, wherein         the first heat exchanger is configured to form a heat exchange         relationship with a cold part of a refrigeration system.         Aspect 5. The air supply system of any of aspect 4, wherein the         first heat exchanger is configured to form the heat exchange         relationship with an evaporator of the refrigeration system.         Aspect 6. The air supply system of any of aspects 1-5, wherein         the first heat exchanger is configured to be positioned inside a         temperature controlled storage unit.         Aspect 7. The air supply system of any of aspects 5-6, wherein         the first heat exchanger is configured to be positioned in an         airflow inside the temperature controlled storage unit.         Aspect 8. The air supply system of any of aspects 1-7, wherein         the second heat exchanger is configured to form a heat exchange         relationship with a hot part of a refrigeration system.         Aspect 9. The air supply system of any of aspects 1-8, wherein         the second heat exchanger is configured to form a heat exchange         relationship with a condenser of the refrigeration system.         Aspect 10. The air supply system of any of aspects 3-9, wherein         the second heat exchanger is configured to form a heat exchange         relationship with an air stream compressed by the air         compressor.         Aspect 11. The air supply system of any of aspects 1-10, further         comprising:     -   a first temperature sensor configured to measure a first         temperature of the air stream directed out of the first heat         exchanger; and     -   a second temperature sensor configured to measure a second         temperature of the air stream directed out of the second heat         exchanger,     -   wherein the air supply system is configured so that the first         temperature and the second temperature meet desired values.         Aspect 12. The air supply system of any of any of aspects 1-11,         wherein the air stream directed out of the second heat exchanger         is directed to an air separation device.         Aspect 13. The air supply system of any of aspects 1-12, wherein         the first heat exchanger is coupled to a refrigeration system so         as to direct a portion of expanded refrigerant into the first         heat exchanger.         Aspect 14. The air supply system of any of aspects 1-13 further         comprising:     -   a third heat exchanger positioned downstream of the second heat         exchanger; wherein the third heat exchanger is coupled to a         refrigerant system so as to direct a portion of refrigerant         compressed by a compressor of the refrigerant system into the         third heat exchanger, and exchange heat with the air stream         directed through the third heat exchanger.         Aspect 15. A transport unit, comprising:     -   a transport refrigeration unit;     -   an air supply system, comprising:         -   a first heat exchanger;         -   a second heat exchanger; and         -   a moisture reduction device;         -   wherein the first heat exchanger is configured to lower a             temperature of an air stream supplied to the air supply             system,         -   the moisture reduction device is configured to remove             moisture in the air stream after the air stream is directed             out of the first heat exchanger; and         -   the second heat exchanger is configured to raise the             temperature of the air stream after the air stream is             directed out of the moisture reduction device; and     -   an air separation device, wherein the air stream form the air         supply system is directed to the air separation device.         Aspect 16. The transport unit of aspect 15, wherein the         transport refrigeration unit further comprising an evaporator,     -   wherein the first heat exchanger is configured to form a heat         exchange relationship with the evaporator of the transport         refrigeration unit.         Aspect 17. The transport unit of any of aspects 15-16, further         comprising a cargo space,     -   wherein the first heat exchanger is configured to be positioned         inside the cargo space of the transport unit.         Aspect 18. The transport unit of any of aspects 15-17, wherein         the transport refrigeration unit further comprises a condenser,         wherein the second heat exchanger is configured to form a heat         exchange relationship with the condenser of the transport         refrigeration unit.         Aspect 19. The transport unit of any of aspects 15-18, further         comprising:     -   a compressor configured to provide the air stream to the air         supply system, wherein the second heat exchanger is configured         to form a heat exchange relationship with the air stream         provided by the air compressor.         Aspect 20. A method of conditioning an air stream for an air         separation device, comprising:     -   providing an air stream;     -   lowering a temperature of the air stream;     -   removing moisture from the air stream with the lowered         temperature;     -   increasing the temperature of the air stream after removing         moisture from the air stream; and     -   directing the air stream into the air separation device.         Aspect 21. The method of conditioning the air stream of aspect         20, further comprising:     -   removing particles from the air stream after removing moisture         from the air stream.         Aspect 22. The method of conditioning the air stream of aspects         20-21, wherein lowering the temperature of the air stream         includes forming a heat exchange relationship with an evaporator         of a transport refrigeration unit.

With regard to the foregoing description, it is to be understood that changes may be made in detail, without departing from the scope of the present invention. It is intended that the specification and depicted embodiments are to be considered exemplary only, with a true scope and spirit of the invention being indicated by the broad meaning of the claims. 

1. An air supply system, comprising: a first heat exchanger; a second heat exchanger; and a moisture reduction device; wherein the first heat exchanger is configured to lower a temperature of an air stream supplied to the air supply system, the moisture reduction device is configured to remove moisture in the air stream after the air stream is directed out of the first heat exchanger; and the second heat exchanger is configured to raise the temperature of the air stream after the air stream is directed out of the moisture reduction device.
 2. The air supply system of claim 1, further comprising: a particle reduction device, wherein the particle reduction device is configured to remove particles in the air stream after the air stream is directed out of the moisture reduction device.
 3. The air supply system of claim 1, wherein an air stream to the air supply system is provided by an air compressor.
 4. The air supply system of claim 1, wherein the first heat exchanger is configured to form a heat exchange relationship with a cold part of a refrigeration system.
 5. The air supply system of claim 4, wherein the first heat exchanger is configured to form the heat exchange relationship with an evaporator of the refrigeration system.
 6. The air supply system of claim 1, wherein the first heat exchanger is configured to be positioned inside a temperature controlled storage unit.
 7. The air supply system of claim 5, wherein the first heat exchanger is configured to be positioned in an airflow inside the temperature controlled storage unit.
 8. The air supply system of claim 1, wherein the second heat exchanger is configured to form a heat exchange relationship with a hot part of a refrigeration system.
 9. The air supply system of claim 1, wherein the second heat exchanger is configured to form a heat exchange relationship with a condenser of the refrigeration system.
 10. The air supply system of claim 3, wherein the second heat exchanger is configured to form a heat exchange relationship with an air stream compressed by the air compressor.
 11. The air supply system of claim 1, further comprising: a first temperature sensor configured to measure a first temperature of the air stream directed out of the first heat exchanger; and a second temperature sensor configured to measure a second temperature of the air stream directed out of the second heat exchanger, wherein the air supply system is configured so that the first temperature and the second temperature meet desired values.
 12. The air supply system of claim 1, wherein the air stream directed out of the second heat exchanger is directed to an air separation device, wherein the air separation device removes carbon dioxide from the air stream and includes at least one of a pressure swing membrane, a cryogenic distillation device, a sorption device, and a catalytic conversion device.
 13. A transport unit, comprising: a transport refrigeration unit; an air supply system, comprising: a first heat exchanger; a second heat exchanger; and a moisture reduction device; wherein the first heat exchanger is configured to lower a temperature of an air stream supplied to the air supply system, the moisture reduction device is configured to remove moisture in the air stream after the air stream is directed out of the first heat exchanger; and the second heat exchanger is configured to raise the temperature of the air stream after the air stream is directed out of the moisture reduction device; and an air separation device, wherein the air stream form the air supply system is directed to the air separation device.
 14. The transport unit of claim 13, wherein the transport refrigeration unit further comprising an evaporator, wherein the first heat exchanger is configured to form a heat exchange relationship with the evaporator of the transport refrigeration unit.
 15. The transport unit of claim 13, further comprising a cargo space, wherein the first heat exchanger is configured to be positioned inside the cargo space of the transport unit.
 16. The transport unit of claim 13, wherein the transport refrigeration unit further comprises a condenser, wherein the second heat exchanger is configured to form a heat exchange relationship with the condenser of the transport refrigeration unit.
 17. The transport unit of claim 13, further comprising: a compressor configured to provide the air stream to the air supply system, wherein the second heat exchanger is configured to form a heat exchange relationship with the air stream provided by the air compressor.
 18. A method of conditioning an air stream for an air separation device, comprising: providing an air stream; lowering a temperature of the air stream; removing moisture from the air stream with the lowered temperature; and increasing the temperature of the air stream after removing moisture from the air stream.
 19. The method of conditioning the air stream of claim 16, further comprising: removing particles from the air stream after removing moisture from the air stream.
 20. The method of conditioning the air stream of claim 16, wherein lowering the temperature of the air stream includes forming a heat exchange relationship with an evaporator of a transport refrigeration unit.
 21. The transport unit of claim 13, wherein the air separation device removes carbon dioxide from the air stream and includes at least one of a pressure swing membrane, a cryogenic distillation device, a sorption device, and a catalytic conversion device.
 22. The method of claim 18, further comprising removing carbon dioxide from the air stream using at least one of a pressure swing membrane, a cryogenic distillation device, a sorption device, and a catalytic conversion device. 